The invention generally relates to electrical switches, and more particularly relates to rocker switches having a two-stage actuating stroke.
DE 195 37 296 A1 details a rocker switch device for a two-stage actuating stroke that is part of an actuating unit for electric window openers of a motor vehicle and comprises a pair of actuating plates underneath a longitudinal middle line of a rocker button. The actuating plates are coupled by elastic connecting arms and form an actuating member in this manner. Each actuating plate loads two pressure switches formed by a switching mat with hollow projections and with contact pieces arranged therein and by a base plate with fixed contact pieces associated with the moveable contact pieces. When the rocker button is actuated it pivots about carrier axle ends of a housing so that the actuated side of the rocker button moves down. This downwardly directed movement is transmitted via the associated actuating plate to the left and right projections, arranged underneath this plate, of the switching mat. The projections are arranged in such a manner that as a result of the differently acting torques at first the left projection is deformed and a circuit is closed by the contact of the contact pieces arranged here and after a further downward movement of the rocker button the right projection is also pressed downward by the actuating plate and another circuit is closed. After the rocker button is released it is automatically returned, which interrupts the closed circuit. The rocker switch device accordingly comprises a plurality of contact pieces and actuating plates that bring about the appropriate switching functions for controlling the electric window opener, which necessitates an extremely complex design of the rocker switch device.
Furthermore, a multi-stage rocker switch is known from DE 196 00 657 C1 that consists substantially of a rocker button pivotably supported on the housing and of four push rods received by a conductor plate, which rods are arranged beneath the rocker button. The conductor plate is arranged inside the housing parallel to a conductor plate. Each push rod acts with a dome of a switch mat that receives a contact piece that makes contact with a fixed contact piece upon a loading of the dome by the associated push rod after the dome is bent in and closes a current path. Each two adjacent domes have a different stability, which has, as a consequence, a bending in upon a different action of force. The two push rods arranged in the area of each front side of the rocker button and loading the corresponding, adjacent domes are actuated by an associated appendage of the rocker button which appendage acts on an intermediate element supported in the conductor plate in such a manner that this element can pivot and also shift vertically. To this end the intermediate element comprises horizontal guide pins resting in corresponding grooves of the conductor plate. The intermediate element is designed as a two-arm lever and a push rod is associated with each lever arm. When the rocker button is actuated, the associated intermediate element is loaded via the appendage of the rocker button with a pressure force opposed by the different pressure forces of the domes. The dome associated with an actuating stroke of a first state bends in, while the intermediate element is shifted vertically as well as pivoted, since the associated lever arm constantly rests on the corresponding push rod on account of the acting forces. Upon an actuating stroke of a second stage the dome adjacent to the first dome also bends in, while the two lever arms are located in a horizontal position and the intermediate element is shifted vertically in the direction of the domes by a further path stretch. The rocker switch is disadvantageous in as far as a very complex switching mechanism is provided for realizing a two-stage actuating stroke.
In addition, EP 0 604 837 A1 teaches a hand-actuated control switch for a raising device with a rocker switch for a two-stage actuating stroke in which a rocker button is pivotably supported in a front plate of a housing. The rocker button is associated with an actuating device comprising two levers for loading switching contacts. The switching contacts are arranged in a series on a conductor plate. The actuating stroke of the first stage is associated in each direction with the particular outer switching contact and the actuating stroke of the second stage is associated in each direction with the central switching contact. Each lever of the actuating device loads one of the outer switching contacts and both levers actuate the central switching contact.
The invention has the problem of creating a rocker switch of the initially cited type that is distinguished by a compact design with the lowest possible number of structural components and with a reliable operation.
The invention solves this problem in that the operating stroke of the first stage is associated in each direction with a switching contact and the actuating stroke of the second stage is associated in each direction with a joint switching contact.
Based on these measures, the rocker switch comprises only three switching contacts for one two-stage actuating stroke, which results in a compact design and a relatively low number of structural components. The particular switching contact of the actuating stroke of the first stage furnishes a signal about the direction in which the rocker button was loaded and initiates a first switch operation. The actuation of the switching contact associated with the actuating stroke of the second stage brings about another signaling that initiates a second switch operation associated with the first switch operation. For example, the particular switching contact associated with the actuating stroke of the first stage initiates an up or down movement of an associated motor vehicle window that is ended after the rocker button has been released. The joint switching contact for the actuating stroke of the second stage controls a movement of the corresponding motor vehicle window up to its end position, the direction of which is given by the particular first-actuated switching contact. A reliable operation of the rocker switch is assured on account of connection of the second switch operation to the first switch operation. The coupling of the operation of the particular first-loaded switching contact to the operation of the joint switching contact can be realized electrically or via an appropriate control of on-board electronic components.
According to an advantageous embodiment of the invention the three switching contacts are arranged in the form of an equilateral triangle. The switching contacts of the actuating stroke of the first stage are each arranged at a corner point of the base and the switching contact of the actuating stroke of the second stage is arranged at the apex of the triangle. It is advantageous if the base of the equilateral triangle runs parallel to a side wall of the housing and its apex is located under a shaft of the rocker button of the opposite side wall. This arrangement of the switching contacts results in a compact design of the rocker switch and a tactile determination of the first and second stages of the actuating stroke. The switching contacts associated with the first stage of the actuating stroke are arranged at a relatively large spacing from the shaft of the rocker button, so that an appropriate lever arm is available to load them, for which reason the actuation of these switching contacts requires a lesser force in comparison to the actuation of the switching contact arranged on the apex, for which no lever arm is available to load it.
The actuating plate is advantageously supported by way of associated studs on the switching contacts under lateral play relative to the housing. The actuating plate and the studs form a unit in order to transfer the motion of the rocker button on the appropriate switching contact or contacts. Furthermore, no support for the freely movable actuating plate is provided.
In order to impart an appropriate stability to the actuating plate and assure a pivoting motion of the actuating plate as a function of the actuating direction of the rocker button, the actuating plate is provided in a purposeful manner with a crosspiece offset off-center to the longitudinal axis of the switch in the direction of the switching contact located at the triangle apex. An appendage of the rocker button rests on this crosspiece on each of the two sides of the rocker button shaft. As a result of the off-center arrangement of the crosspiece the actuating plate pivots upon an introduction of force on one side via the associated appendage about the corresponding side of the triangle in which side the switching contacts are arranged. Furthermore, the actuating plate is held between the switching contacts and the appendages of the rocker button so that no shifting of the actuating plate due to vibration occurs.
The crosspiece of the actuating plate preferably displays a semicircular clear space for the shaft of the rocker button. The clear space makes possible the pivoting movement of the actuating plate, that does not take place perpendicularly to the shaft but rather about the corresponding side of the triangle, for which reason the actuating plate readily rotates in this instance.
The rocker button advantageously comprises two opposing support lugs for receiving the shaft. Furthermore, the shaft advantageously engages in support bores in the side walls of the housing, with a disk arranged between the side wall and the support lug of the rocker button in each instance, which assures a reliable support of the rocker button. The disk arranged between the particular side wall of the housing and the corresponding support lug of the rocker button reduces the friction between these components when the rocker button is pivoted.
In an alternative embodiment of the invention the shaft is designed as axle ends formed on the opposite support lugs of the rocker button which axle ends engage in corresponding support bores in the side walls of the housing. This embodiment creates a reliable support of the rocker button in the housing with a relatively low number of individual parts to be mounted.
According to an advantageous further development of the concept of the invention the switching contacts are designed as snap disks that cooperate with contact paths of a punched grid set in the housing bottom. In an alternative embodiment the switch contacts are designed as snap disks that cooperate with contact paths of a conductor plate lying on the bottom of the housing. The snap disks have a pre-tension that assures the return movement of the rocker button. The punched grid is injected during the injection-molding process for manufacturing the housing into its bottom.
Each snap disk is preferably held via two lock bolts on the sides of the housing. The mounting of the snap disks takes place without great expenditure by simply inserting the snap disks between the lock bolts, which assure a sufficient fixing.